How do I get permanent lines in screen fixed?

I've had my e-reader for a long while. And for a while it had an issue where half the screen would not refresh with text layering on top of previous pages. It still does this on the occasion, however now it mostly just has a few permanent lines in the screen which can be seen on all displays. And was wondering if there was a software workaround d to fix this, and if not, where I could possibly get it fixed as it is long out of warranty . I am located in Melbourne, Australia.